Preparation, structure, and reactivity of bicyclic benziodazole: a new hypervalent iodine heterocycle

Abstract

A new bicyclic organohypervalent iodine heterocycle derivative of benziodazole was prepared by oxidation of 2-iodo-N,N’-diisopropylisophthalamide with m-chloroperoxybenzoic acid under mild conditions. Single crystal X-ray crystallography of this compound revealed a five-membered bis-heterocyclic structure with two covalent bonds between the iodine atom and the nitrogen atoms. This novel benziodazole is a very stable compound with good solubility in common organic solvents. This compound can be used as an efficient reagent for oxidatively assisted coupling of carboxylic acids with alcohols or amines to afford the corresponding esters or amides in moderate yields.

Pseudocyclic bis-N-heterocycle-stabilized iodanes – synthesis, characterization and applications

“…17a, X = OTs, 0% 17b, X = OTf, 0% benziodoxoles and benziodazoles, while the distorted T-shaped geometry appears to be the most bent among bicyclic hypervalent iodine compounds. [37][38][39][40] Furthermore, the coordination of one MeOH molecule (2.712 Å) and a weak interaction of the two expected triflate counterions (2.808 Å and 3.206 Å) with the iodine atom were observed. Finally, we investigated the reactivity of these hypervalent iodine compounds.…”

Heterocyclic Hypervalent Iodine(III) Compounds with Fused Benziodazole and Tetrazole Rings (I-Substituted Tetrazolo[1,5-b][1,2]Benziodazoles)

“…69 However, it is comparable and only marginally shorter than the exocyclic HV I-O bond in the a related heterocylic compound with a hydroxy ligand, I-hydroxybenziodoxolone (2.00 Å), 70 and in the even more closely related benziodazole with methoxy ligands (2.23 Å). 54 More noteworthy is the length of the endocyclic I-N bond (2.37 Å), which was markedly longer than the I-N bonds in a bicyclic benziodazole with two HV I-N bonds (2.18 Å each), 71 I-chlorobenziodoazole (2.11 Å), 72 I-chlorosulfoximine (2.10 Å), I-trifluoromethylsulfoximine (2.28 Å), 73 and I-acetoxybenziodoazole (2.10 Å). 53 At the same time, the I-N bond in BIAT-OH 5 is shorter than I-N bonds with pronounced ionic character, e.g., in I-phenylbenziodazole (2.45), 74 and other compounds with pyridine coordinated to the HV iodine(III) atom (2.41-2.44 Å).…”

Heterocyclic Hypervalent Iodine(III) Compounds with Fused Benziodazole and Tetrazole Rings (I-Substituted Tetrazolo[1,5-b][1,2]Benziodazoles)

“…69 However, it is comparable and only marginally shorter than the exocyclic HV I-O bond in the a related heterocylic compound with a hydroxy ligand, I-hydroxybenziodoxolone (2.00 Å), 70 and in the even more closely related benziodazole with methoxy ligands (2.23 Å). 54 More noteworthy is the length of the endocyclic I-N bond (2.37 Å), which was markedly longer than the I-N bonds in a bicyclic benziodazole with two HV I-N bonds (2.18 Å each), 71 I-chlorobenziodoazole (2.11 Å), 72 I-chlorosulfoximine (2.10 Å), I-trifluoromethylsulfoximine (2.28 Å), 73 and I-acetoxybenziodoazole (2.10 Å). 53 At the same time, the I-N bond in BIAT-OH 5 is shorter than I-N bonds with pronounced ionic character, e.g., in I-phenylbenziodazole (2.45), 74 and other compounds with pyridine coordinated to the HV iodine(III) atom (2.41-2.44 Å).…”